The extraction of gelatin from Caspian Sea( Huso Huso) skin and survey its rheological properties

Gelatine is one colloidal protein that it used the most widely in the food, pharmaceutical, medical and military industry. Annually , considerable amounts of gelatine for different uses were transfered into the country. In other hand, the Caspian Sea is the rich sources of fishes such as Beluga sturgeon, carp, Caspian White fish and etc, that significant amounts of residue which is lost as waste that can be a good source to extract gelatine. In this study the effect of different extraction methods gelatine (I, II, III and IV) of beluga skin was examined. Results showed that the highest melting point, yeild and absolute viscosity gelatin extracted were observed in II, III and III methods, respectively. The gelatine viscosity decrease with increasing concentration of sodium hydroxide (method II and IV), and with smaller amounts of (Methods I and III), increases. Also, using the Arrhenius equation to determine the relation between viscosity gelatine and temperature were used, then activation energy calcuated in the range 16.31 to 32.66 kJ / mol respectively. Finally, using exponential and power models viscosity gelatine was fitted with Brix. Modeling results indicated that the exponential model was more accurate in predicting the gelatine absolute viscosity